This application is for funds to purchase the BIAcore 2000 plasmon resonance instrument. At the present time the University of Florida has no optical sensore to measure macromolecular interactions in real time. The BIAcore plasomon resonance instrument, which is state-of-the-art technology for analyzing protein ligand interactions, as well as a wide variety of ligand-receptor interactions, will be important for a number of research projects that require this capability. The main features that we require are the multichannel capabilities, the ability to test ligands that are as small as 200 Da and present in low concentrations - - down to 1 pM. The BIAcore technology includes a wide range of sensor surfaces, a requirement for the diverse projects that are being proposed. We will be able to measure protein-protein interactions as well as protein-DNA interactions using multiple avenues for immobilizing one of the reactants to the sensor chip. For several of the projects it will be important to be able to measure both weak and strong interactions, for example, as they relate to the binding affinities of antibodies for their ligands. Finally, BIAcore 2000 is simple and reliable and an ideal system for a multi-user group. The projects proposed address intermolecular interactions in different systems including: Nucleic acids, experimental paleobiochemical, combinatorial, and molecular recognition studies that combine organic synthesis, molecular biology, biophysics, and evolutionary theory, Mechanisms of catalysis and inhibition of enzymes is the aspatic proteinase and serine proteinase families, Structure-function relationship of the FMRFamide family of neuropeptides, Signal transduction interactions that regulate transcription factor complexes, Determination of the regions of arrestin that bind to rhodopsin and the regions of rhodopsin that bind to arrestin, Role of adhesion related molecules in Corneal Epithelial Integrity, and The properties of beta- chemokine binding to the orthopoxvirus encoded, secreted 35 kDa protein.